Keijiro Fukazawa

Cellular localization of rat Isk protein in the stria vascularis by immunohistochemical observation.

A novel rat membrane protein, termed Isk protein, that exhibits a voltage-dependent potassium channel activity was first reported through molecular cloning combined with an electrophysiological assay (Takumi et al., 1988). In the present study, we made an attempt to identify the cellular localization of the rat Isk protein in the stria vascularis using two types of antibodies that specifically react with the distinct parts of the rat Isk protein. Immunohistochemical analysis showed that the rat Isk protein was present only on the endolymphatic surface of the marginal cell. The possibility that the Isk protein is involved in potassium permeation in the luminal membrane of the marginal cell will be also discussed.

Rate of recovery of taste function after preservation of chorda tympani nerve in middle ear surgery with special reference to type of disease.

To study the recovery of function of the chorda tympani nerve, we examined by electrogustometry 79 patients (83 ears) with both preoperative normal function of the nerve and operative preservation of the nerve, every 2 days during hospitalization and at 6 months after surgery. For symptoms such as tongue numbness and taste disturbance, patients with noninflammmatory (NI) diseases (13/20 or 65.0%) showed a significantly higher rate of symptoms than did patients with chronic otitis media (COM; 13/35 or 37.1%) at 2 weeks after surgery (p = .032). The patients with NI diseases (5/20 or 25.0%) tended to show a higher rate of symptoms than did the COM patients (2/35 or 5.7%) or cholesteatoma patients (2/28 or 7.1%) at 6 months after surgery. The rate of recovery of the EGM threshold to normal at 2 weeks after surgery was significantly lower in NI disease patients (6/20 or 30.0%) than in COM patients (23/ 35 or 62.9%) or cholesteatoma patients (19/28 or 67.9%; p = .015 and .008, respectively). Thus, the patients with NI diseases had postoperative symptoms and elevation of EGM threshold more frequently than did the patients with inflammatory diseases.

Olfactory dysfunction in patients with head trauma

OBJECTIVE There are few reports about following up olfactory acuity of the patients who have post-traumatic olfactory dysfunction. In this study, we studied about patients with post-traumatic olfactory dysfunction for a short period under a treatment. METHODS The olfactory function of 27 patients with head trauma was studied. The olfactory acuities of all the patients were examined using olfactory tests before the treatment, and 18 patients were examined again after the treatment. Olfactory functions were evaluated in 26 patients by T&T olfactometry and in 27 patients by Alinamin test. All of the patients were treated with a local injection of suspended steroid solution into the nasal mucosa [J Otolaryngol Jpn 102 (1999) 1175]. RESULTS Before the treatment, 16 patients (61.5%) presented anosmia, five patients (19.2%) presented severe hyposmia, three patients (11.5%) presented moderate hyposmia, and two patients (7.7%) presented mild hyposmia. Eighteen cases (69.2%) were negative for the Alinamin test and eight cases (30.8%) were positive. The improvement rates of recognition and detection thresholds by T&T olfactometry were 35.3 and 23.5%, respectively. CONCLUSION Olfactory dysfunction caused by head trauma can be recovered to a limited degree in some cases by the local injection of steroid within the relatively short period from the start of the therapy.

Nerve growth factor applied onto the olfactory epithelium alleviates degenerative changes of the olfactory receptor neurons following axotomy.

The olfactory neuroepithelium of the mammalian nervous system manifests continuous neurogenesis throughout life. Recent studies suggest that neurotrophic factors and their receptors may play a role in the regulation of development and regeneration in the olfactory system. However, there have been very few in vivo studies investigating the effect of exogenous neurotrophic factors in the olfactory system. In the present study, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were administered into the rat olfactory mucosa for 5 days just after the transection of the olfactory nerve. We then examined the effect of exogenous neurotrophic factors on the degenerative changes in axotomized olfactory receptor neurons (ORNs). Further, we examined the location of their receptors, Trk A and Trk B. We found that both mature and immature ORNs expressed more intense signals for olfactory marker protein and beta-tubulin mRNAs, respectively, when NGF was applied to the axotomized olfactory neuroepithelium for 5 days, compared to the ORNs of saline-treated controls. BDNF at a 10 microg total dose did not show this effect. The effect of NGF applied onto the olfactory epithelium is consistent with the immunohistochemical finding that Trk A was present in the dendrites and axon bundles in normal and axotomized ORNs. These results suggest that NGF may protect the degenerative changes in mature and immature ORNs following axotomy through the binding to the Trk A receptor located on the surface of the olfactory epithelium.

Difficulty of diagnosing Wegener's granulomatosis in the head and neck region

OBJECTIVE The objective of this study was to review the various clinical features associated with Wegeners granulomatosis (WG) in the head and neck region and to discuss the difficulty of diagnosing patients with early stage WG. METHODS Between January 1998 and August 2007, WG was diagnosed and treated in 16 patients at the Department of Otolaryngology, Hyogo College of Medicine. Clinical and operating records of these patients were analyzed retrospectively. Diagnosis was based on the Japanese criteria proposed by the Japanese Ministry of Health and Welfare in 1998. RESULTS Ten patients (62.5%) had a definite diagnosis of WG, and the other six patients (37.5%) had a probable diagnosis of WG. The period from the onset to diagnosis was between 1 month and 30 years. The generalized form of WG was observed in three patients (18.8%), and the limited form of WG was observed in the other 13 patients (81.2%). Nasal, aural, and ophthalmic symptoms were initially presented in 10, 3, and 3 patients, respectively. Cytoplasmic pattern antineutrophil cytoplasmic antibodies (cANCAs) and perinuclear pattern ANCA (pANCA) were positively detected in 68.8% (11/16) and 27.2% (3/11) of the patients, respectively. Five of 14 patients (35.7%) had pathologic features of WG in biopsy samples from the head and neck region. Three patients in whom a diagnosis of WG was difficult are presented, and immediate lessons of our experience were discussed. CONCLUSIONS This study emphasized the difficulty of diagnosing WG, particularly at an early stage and when limited to the head and neck region. The biggest challenge faced in diagnosing WG is that it requires a high index of suspicion. When WG was suspected, we should obtain an accurate medical history from patients and repeat serologic and histopathologic examinations.

Hair cell regeneration in the chick inner ear following acoustic trauma: ultrastructural and immunohistochemical studies

The regeneration of hair cells in the chick inner ear following acoustic trauma was examined using transmission electron microscopy. In addition, the localization of proliferation cell nuclear antigen (PCNA) and basic fibroblast growth factor (b-FGF) was demonstrated immunohistochemically. The auditory sensory epithelium of the normal chick consists of short and tall hair cells and supporting cells. Immediately after noise exposure to a 1500-Hz pure tone at a sound pressure level of 120 decibels for 48 h, all the short hair cells disappeared in the middle region of the auditory epithelium. Twelve hours to 1 day after exposure, mitotic cells, binucleate cells and PCNA-positive supporting cells were observed, and b-FGF immunoreactivity was shown in the supporting cells and glial cells near the habenula perforata. Spindle-shaped hair cells with immature stereocilia and a kinocilium appeared 3 days after exposure; these cells had synaptic connections with the newly developed nerve endings. The spindle-shaped hair cell is considered to be a transitional cell in the lineage of the supporting cell to the mature short hair cell. These results indicate that, after acoustic trauma, the supporting cells divide and differentiate into new short hair cells via spindle-shaped hair cells. Furthermore, it is suggested that b-FGF is related to the proliferation of the supporting cells and the extension of the nerve fibers.

An immunohistochemical and electrophysiological study on Isk protein in the stria vascularis of the guinea pig

SummaryThe reaction product against rat Isk protein antibody was demonstrated on the endolymphatic surface of the marginal cell of the guinea pig, using an immunohistochemical method. Clofilium, a potassium channel blocker which has been previously found to block rat kidney Isk channels, decreased the endocochlear potential (EP) when applied by perilymphatic perfusion and iontophoresis into endolymph. This finding of a decreased EP supports the presence of Isk protein on the endolymphatic surface of the marginal cell.

Argon plasma surgery for the inferior turbinate of patients with perennial nasal allergy.

Objectives Argon plasma coagulation (APC) is a new electrosurgical modality. The advantages of APC are coagulating of the target tissue without contact and the creation of uniformly deep devitalized and coagulated zones. The objectives of the present study were to determine the clinical effects of APC for the inferior turbinate of patients with nasal allergy and to clarify the histological changes in the mucosa after APC.

Reevaluation of bilateral same-day surgery for bilateral perforated chronic otitis media.

To evaluate the results of bilateral same-day surgery for bilateral perforated chronic otitis media in comparison with our previous report. Study Design: Prospective study. Patients: Seventeen patients ranging in age from 5 to 70 years (mean, 52.5 yr), with bilateral perforated chronic otitis media. Methods: Two hundred cases of chronic otitis media were operated on at the Department of Otolaryngology, Hyogo College of Medicine from December 1998 to November 2002. Fifty-nine patients (29.5%) had bilateral disease and 17 patients (8.5%) underwent bilateral same-day surgery. Results: The postoperative air-bone gap was less than 10 dB on both sides in 5 of 17 (29%) and less than 20 dB in 15 of 17 (88%). The postoperative hearing level was less than 20 dB in both ears in 4 of 17 (24%), less than 30 dB in 7 of 17 (41%), and less than 40 dB in 10 of 17 (59%). The rate of closure of the ear drum was 20 of 22 (91%) in the simple underlay myringoplasty series and 9 of 12 (75%) in the conventional myringoplasty/tympanoplasty series. The rate of closure of the ear drum on both sides was successful in 4 of 5 (80%) that underwent simple underlay myringoplasty/simple underlay myringoplasty and 8 of 12 (67%) that underwent simple underlay myringoplasty/conventional myringoplasty/tympanoplasty, whereas that on at least one side was successful in 100%. Conclusion: Bilateral same-day surgery for bilateral perforated chronic otitis media is possible if operative indications are considered. Furthermore, it will help patients save time and money.

Clinical study of flavor disturbance.

Objective We have observed that, in cases of smell loss, patients often complain of taste loss as well even though they actually have normal gustatory acuity according to gustatory tests; we have defined such symptoms as “flavor disturbance”. The clinical features of flavor disturbance are reported in this paper. Material and Methods A total of 297 patients (99 males, 198 females; mean age 55.5 years) were treated for olfactory disturbance at the hospital of Hyogo College of Medicine between July 1995 and August 2001. Sixty-six out of 297 patients (22.5%) also experienced taste disturbance, and 49 of these 66 cases were evaluated by means of smell and taste tests. These 49 patients who complained of taste and smell loss were classified into two groups according to the results of their smell and taste tests. Patients who only complained of olfactory disturbance were also reviewed. Results There was no relationship between the severity of olfactory disturbance and the degree of flavor disturbance. The incidence of flavor disturbance was high in patients with sudden olfactory disturbance after upper respiratory tract infection or head trauma and low in those with slowly progressive olfactory disturbance. The symptoms of flavor disturbance improved regardless of whether smell was improved or not. Conclusions The patients with flavor disturbance tended to misrecognize that they had taste loss because of sudden smell loss, and there were more of these cases than we expected. When patients with smell and taste loss are treated, flavor disturbance should also be considered.